A new smart and responsive material can stiffen up like a worked-out muscle, say the Iowa State University engineers who developed it.

Stress a muscle and it gets stronger. Mechanically stress the rubbery material - say with a twist or a bend - and the material automatically stiffens by up to 300 percent, the engineers said. In lab tests, mechanical stresses transformed a flexible strip of the material into a hard composite that can support 50 times its own weight.

Material - Energy - Sources - Heat - Light

This new composite material doesn't need outside energy sources such as heat, light or electricity to change its properties. And it could be used in a variety of ways, including applications in medicine and industry.

The material is described in a paper recently published online by the scientific journal Materials Horizons. The lead authors are Martin Thuo and Michael Bartlett, Iowa State assistant professors of materials science and engineering. First authors are Boyce Chang and Ravi Tutika, Iowa State doctoral students in materials science and engineering. Chang is also a student associate of the U.S. Department of Energy's Ames Laboratory.

Iowa - State - Startup - Funds - Thuo

Iowa State startup funds for Thuo and Bartlett supported development of the new material. Thuo's Black & Veatch faculty fellowship also helped support the project.

Development of the material combined Thuo's expertise in micro-sized, liquid-metal particles with Bartlett's expertise in soft materials such as rubbers, plastics and gels.

Combination

It's a powerful combination.

The researchers found a simple, low-cost way to produce particles of undercooled metal - that's metal that remains liquid even below its melting temperature. The tiny particles (they're just 1 to 20 millionths of a meter across) are created by exposing droplets of melted metal to oxygen, creating an oxidation layer that coats the droplets and stops the liquid metal from turning...